This invention relates to fast connections, exemplified by connecting or coupling devices operable to rapidly couple or uncouple lengths of pipe.
We are familiar with a variety of fast connections having, in the perimeter of the male element, a groove whose front flank is substantially perpendicular to the axis and, in the female element, a bolt that can receive an axial displacement and whose rear flank, on locking, engages behind the front flank of the male element. The locking, in these models of connections is insured by an automatic ratchet mechanism, the bolt being urged elastically by a spring in the radial locking direction and the nose of the male element has a truncated ramp with which a ramp provided on the bolt will cooperate to shift the pawl from its locking position until the pawl falls back into the groove of the male element.
In many forms of embodiment, and for example as described in French published patent document FR-A-1,402,040, the displacement of the bolt to insure unlocking against the thrust of the spring takes place by repelling the bolt constituted by a cylindrical ring by depression of a pushbutton accessible through an orifice in the peripheral surface of the female element. This embodiment has the drawback that the pushbutton can be depressed accidentally and, above, all that the displacement of the bolt under the influence of the spring can be blocked, for example by dirt entering the pushbutton recess.
The fast connection of the type concerned by the invention described in French published patent document FR-A-1,363,394 does not have the above drawbacks because the bolt is shifted from its locking position against the action of the spring, by an axial sleeve mounted in the female element, a sleeve inside which the nose of the male element fits, this sleeve being subject to the thrust axially inward of the female element by action on a peripheral jacket surrounding the said element in order, by cooperation of its truncated end with a truncated area in the front face of the bolt, to shift the bolt radially. This arrangement, however, has the drawback that this unlocking sleeve substantially increases the diameter of the female element for a given clear section of the connection.
French published patent document FR-A-1,487,324 proposes to embody the bolt in the form of a part sliding in a guide in the body of the female mouthpiece, the end of the bolt opposite the return spring cooperating with a ramp formed in the inner wall of a ring sliding axially so that the bolt will be free to return to the engaged position or be repelled for unlocking against the action of the spring. In order to obtain a precise positioning of the bolt in unlocked position, the sliding bolt must be guided without play, and then there are risks of jamming and blocking the bolt, particularly in unlocked position.
We also know of ball-type fast connections, but the balls which engage in a groove in the male element on being repelled by a ring sliding longitudinally on the female connection, constitute the locking members by themselves.
One general drawback of the fast connections used in particular for connecting pipelines of gas under pressure is that the pressure which remains as a general rule in the piping integral with the male element will cause, at the moment of unlocking, an abrupt separation of the connecting elements with abrupt deformations of the flexible piping.
There has already been a proposal, for example in Swiss published patent document CH-A-368,669, of a connection in which the male element is unlocked in two stages, the locking being insured by two peripheral rows of balls engaging in a peripheral groove of wide longitudinal width in the male element, the ring controlling the eclipsing of the balls having two parallel internal peripheral grooves. Since the flawless operation of the two locking devices is extremely important in this application for reasons of safety, the transportation of the case of locking by radially acting bolt raised the same problem as set forth above with the consequences resulting from the jamming of a bolt which could be very serious.